This invention relates generally to an imaging member viewed in reflection and more particularly to such an imaging member comprising a front surface reflection rejection layer.
There are known in the art many different types of imaging and display systems including, for example, electrophoretic, electroluminescent, photoelectrophoretic, ferroelectric, and liquid crystal. In such systems it is known to form images by the application of various stimuli to the imaging materials. In one preferred embodiment a layer of imaging material is arranged adjacent a substantially transparent electrode and images are formed by steps including applying an electrical field across the imaging layer. In a well known embodiment a layer of imaging material is arranged between a pair of planar full frame electrodes one of which may include a photoconductive insulating layer. In many instances the images formed in these types of imaging and display members are made up of areas which scatter light and those which do not scatter light. Depending, inter alia, upon the particular electrode system the images may be read out in transmission or reflection. Moreover, the images may typically be viewed directly by an observer or may be used in other ways such as, for example, where the image is projected onto means adapted to make a hard copy reproduction thereof.
Imaging and display members of this type are capable of providing excellent images; however, some difficulty may be encountered in reading out the images which may adversely affect device performance. For example, when the reflection readout mode is utilized the contrast of an image perceived by a viewer is typically limited by spurious front surface reflections. Such limitations may in some instances render direct readout virtually impossible and may dictate the use of image enhancement means such as polarizers which has heretofore been the case with some liquid crystal imaging members. The polarizers typically exploit the birefringence of the liquid crystal materials and typically provide greatly increased contrast. However, the necessity of employing polarizers to read out the image is not a completely satisfactory expedient because, inter alia, they typically require off-axis optics and thus complicate the imaging system. Additionally, polarizers generally cause relatively large light losses which is undesirable. It would be highly desirable to minimize any loss in image contrast caused by light reflections when an imaging or display member is read out in reflection.